KR102386370B1 - Plasma processing apparatus - Google Patents

Abstract

(Problem) Suppression of abnormal discharge near exhaust port.
(Solution Means) The plasma processing apparatus includes a processing container, a mounting table, a gas supply mechanism, an exhaust mechanism, a plasma generation mechanism, and a bias power supply mechanism. The processing container accommodates the substrate. The mounting table is provided in the processing container and mounts the substrate. The gas supply mechanism supplies the processing gas into the processing container. The exhaust mechanism exhausts the gas in the processing container through the exhaust pipe. The plasma generating mechanism generates plasma in the processing vessel by converting the processing gas supplied into the processing vessel into plasma. The bias power supply mechanism supplies high frequency power for bias to the mounting table. The exhaust port of the exhaust pipe connected to the wall portion of the processing vessel is provided with a mesh member made of a conductive member and connected to a ground potential. The mesh member is provided with a plurality of through holes penetrating in the thickness direction of the mesh member. Further, in each through hole, the ratio of the thickness of the mesh member to the width of the opening is 0.67 or more.

Description

Plasma processing apparatus {PLASMA PROCESSING APPARATUS}

Various aspects and embodiments of the present disclosure relate to a plasma processing apparatus.

A process of plasma processing, such as dry etching, is included in the manufacturing process of a semiconductor device in many cases. In plasma processing, a gas is introduced into a processing container, and the gas is excited by a high frequency wave or the like, thereby becoming plasma. Then, the substrate is subjected to processing such as etching by ions or radicals contained in the plasma. Reaction by-products generated in processing such as etching become volatile gases and are exhausted from the inside of the processing container.

Plasma generated in the processing space above the substrate may enter the exhaust path along with the flow of the gas. When the plasma enters the exhaust path, an exhaust device or the like provided in the exhaust path is damaged by the plasma. Therefore, in order to suppress the intrusion of plasma into the exhaust path, a baffle plate provided with a plurality of through holes between the processing space and the exhaust path may be provided. The baffle plate is made of metal or the like, and is connected to a ground potential.

Patent Document 1: Japanese Patent Laid-Open No. 2009-200184

The present disclosure provides a plasma processing apparatus capable of suppressing abnormal discharge in the vicinity of an exhaust port.

One aspect of the present disclosure is a plasma processing apparatus including a processing vessel, a mounting table, a gas supply mechanism, an exhaust mechanism, a plasma generation mechanism, and a bias power supply mechanism. The processing container accommodates the substrate. The mounting table is provided in the processing container and mounts the substrate. The gas supply mechanism supplies the processing gas into the processing container. The exhaust mechanism exhausts the gas in the processing container through the exhaust pipe. The plasma generating mechanism generates plasma in the processing vessel by converting the processing gas supplied into the processing vessel into plasma. The bias power supply mechanism supplies high frequency power for bias to the mounting table. The exhaust port of the exhaust pipe connected to the wall portion of the processing vessel is provided with a mesh member made of a conductive member and connected to a ground potential. The mesh member is provided with a plurality of through holes penetrating in the thickness direction of the mesh member. Further, in each through hole, the ratio of the thickness of the mesh member to the width of the opening is 0.67 or more.

According to various aspects and embodiments of the present disclosure, abnormal discharge in the vicinity of the exhaust port can be suppressed.

1 is a longitudinal sectional view showing an example of a plasma processing apparatus according to a first embodiment of the present disclosure.
2 is a cross-sectional view showing an example of the plasma processing apparatus according to the first embodiment of the present disclosure.
3 is an enlarged cross-sectional view showing an example of an exhaust mechanism according to the first embodiment of the present disclosure.
4 is a plan view showing an example of a mesh member according to the first embodiment of the present disclosure.
It is an enlarged view for demonstrating an example of arrangement|positioning of a through-hole.
6 is an enlarged cross-sectional view showing an example of a mesh member according to the first embodiment of the present disclosure.
It is a figure which shows another example of the shape of the opening of a through-hole.
It is a figure which shows an example of the experiment result in 1st Embodiment of this indication.
It is a figure which shows an example of the experiment result in 1st Embodiment of this indication.
It is a figure which shows an example of the experiment result in 1st Embodiment of this indication.
It is a figure which shows an example of the experiment result in 1st Embodiment of this indication.
12 is a schematic diagram for explaining an example of a relationship between a through hole and plasma.
13 is a schematic diagram for explaining an example of a relationship between a through hole and plasma.
14 is a plan view showing an example of a mesh member in a comparative example.
15 is an enlarged cross-sectional view showing an example of an exhaust mechanism in a comparative example.
It is a figure which shows an example of the experimental result in a comparative example.
It is a figure which shows an example of the amount of shearing of a mesh member.
18 is an enlarged cross-sectional view showing an example of an exhaust mechanism according to a second embodiment of the present disclosure.
It is a figure which shows an example of the experiment result in 2nd Embodiment of this indication.
It is a figure which shows an example of the experiment result in 2nd Embodiment of this indication.
It is a figure which shows an example of the experiment result in another embodiment of this indication.

EMBODIMENT OF THE INVENTION Below, embodiment of the disclosed plasma processing apparatus is demonstrated in detail based on drawing. In addition, the disclosed plasma processing apparatus is not limited by the following embodiment.

However, in plasma processing, when the pressure in the processing vessel increases or the power of the high-frequency bias supplied to the stage on which the substrate is mounted increases, abnormal discharge in which plasma enters the through hole of the baffle plate in the vicinity of the exhaust port occurs. easier to do When abnormal discharge occurs, the plasma state in the vicinity of the substrate fluctuates, making it difficult to perform stable plasma processing on the substrate.

Accordingly, the present disclosure provides a technique capable of suppressing abnormal discharge in the vicinity of the exhaust port.

(First embodiment)

[Configuration of plasma processing device 1]

1 is a longitudinal cross-sectional view showing an example of a plasma processing apparatus 1 according to a first embodiment of the present disclosure. 2 is a cross-sectional view showing an example of the plasma processing apparatus 1 according to the first embodiment of the present disclosure. A cross-section A-A of the plasma processing apparatus 1 illustrated in FIG. 1 corresponds to FIG. 2 , and a cross-section B-B of the plasma processing apparatus 1 illustrated in FIG. 2 corresponds to FIG. 1 . The plasma processing apparatus 1 according to the present embodiment generates an inductively coupled plasma (ICP), and uses the generated plasma to perform plasma processing such as etching, ashing, and film formation on a rectangular substrate G. do. In this embodiment, the board|substrate G is a glass substrate for FPD (Flat Panel Display), for example.

The plasma processing apparatus 1 includes a main body 10 and a control apparatus 20 . The main body 10 has, for example, a prismatic airtight processing container 101 whose inner wall surface is formed of a conductive material such as anodized aluminum. The processing vessel 101 is grounded. The processing chamber 101 is partitioned vertically by a dielectric wall 102 , and the upper surface of the dielectric wall 102 serves as an antenna chamber 103 in which an antenna is accommodated, and the lower surface of the dielectric wall 102 . This is the processing chamber 104 in which plasma is generated. The dielectric wall 102 is made of ceramics such as Al ₂ O ₃ or quartz, and constitutes the ceiling wall of the processing chamber 104 .

In the processing chamber 101 , a support shelf 105 protruding inward is provided between the side wall 103a of the antenna chamber 103 and the side wall 104a of the processing chamber 104 . The dielectric wall 102 is supported by a support shelf 105 .

A shower housing 111 for supplying a processing gas into the processing chamber 104 is fitted in a lower portion of the dielectric wall 102 . The shower housing 111 is configured in a beam shape, for example, and is suspended from the ceiling of the antenna chamber 103 by a plurality of suspenders (not shown).

The shower housing 111 is made of, for example, a conductive material such as aluminum whose surface has been subjected to an anodization treatment. A gas diffusion chamber 112 extending in a horizontal direction is formed inside the shower housing 111 . A plurality of gas discharge holes 112a extending downward communicate with the gas diffusion chamber 112 .

A gas supply pipe 121 is provided in approximately the center of the upper surface of the dielectric wall 102 so as to communicate with the gas diffusion chamber 112 of the shower housing 111 . The gas supply pipe 121 penetrates from the ceiling of the antenna chamber 103 to the outside of the processing chamber 101 , and is connected to the gas supply mechanism 120 .

The gas supply mechanism 120 includes a gas supply source, a flow controller such as an MFC (Mass Flow Controller), and a valve. The flow controller controls a flow rate of the process gas supplied from the gas supply source while the valve is open, and supplies the process gas with the controlled flow rate to the gas supply pipe 121 . The processing gas is, for example, O ₂ gas, a mixed gas of O ₂ gas and CF ₄ gas, or the like.

The processing gas supplied from the gas supply mechanism 120 is supplied to the gas diffusion chamber 112 in the shower housing 111 through the gas supply pipe 121 , and is diffused in the gas diffusion chamber 112 . Then, the processing gas diffused in the gas diffusion chamber 112 is discharged to the space inside the processing chamber 104 through the gas discharge hole 112a on the lower surface of the shower housing 111 .

An antenna 113 is disposed in the antenna chamber 103 . The antenna 113 has an antenna wire 113a formed of a metal with high conductivity, such as copper. The antenna wire 113a is formed in an arbitrary shape such as an annular shape or a spiral shape. The antenna 113 is spaced apart from the dielectric wall 102 by a spacer 117 made of an insulating member.

One end of a power feeding member 116 extending above the antenna chamber 103 is connected to a terminal 118 of the antenna wire 113a. One end of a power feed line 119 is connected to the other end of the power feed member 116 , and a high frequency power supply 115 is coupled to the other end of the feed line 119 via a matching device 114 . The high-frequency power supply 115 supplies, for example, high-frequency power with a frequency of 13.56 MHz to the antenna 113 via the matching unit 114 , the feed line 119 , the power feed member 116 , and the terminal 118 . Thereby, an induced electric field is formed in the processing chamber 104 below the antenna 113 . The processing gas supplied from the shower housing 111 is converted into plasma by the induced electric field formed in the processing chamber 104 , and an inductively coupled plasma is generated in the processing chamber 104 . The high frequency power supply 115 and the antenna 113 are examples of a plasma generating mechanism.

A mounting table 130 on which the substrate G is mounted is disposed on the bottom wall 104b of the processing chamber 104 with a spacer 126 formed in a rectangular shape made of an insulating member therebetween. The mounting table 130 includes a base material 131 provided on the spacer 126 , and a protective member 132 formed of an insulating member and covering a sidewall of the base material 131 . The base material 131 has a rectangular shape corresponding to the shape of the substrate G, and the entire mounting table 130 is formed in a square plate shape or a square column shape. The spacer 126 and the protective member 132 are made of insulating ceramics such as alumina. In addition, an electrostatic chuck (not shown) for holding the substrate G is formed on the mounting surface on which the substrate G is mounted on the upper surface of the substrate 131 , and while plasma processing is being performed, the substrate G is mounted on a mounting table ( 130) is fixed.

A matching device 152 and a high frequency power supply 153 are connected to the base 131 via a power supply line 151 . The high frequency power supply 153 supplies the high frequency power for bias to the base material 131 via the matching device 152 and the power supply line 151 . The high frequency power supply 153 is an example of a bias power supply mechanism. When the high frequency power for bias is supplied to the base material 131 via the power supply line 151 and the matching device 152 , ions are attracted to the substrate G disposed above the base material 131 . The frequency of the high frequency power supplied to the base material 131 by the high frequency power supply 153 is, for example, a frequency in the range of 50 kHz to 10 MHz, for example, 6 MHz.

A pipe 133 for supplying a heat transfer gas such as He gas is provided between the substrate G and the electrostatic chuck on the substrate 131 . Since the substrate G is held by the electrostatic chuck, a predetermined pressure can be applied between the substrate G and the electrostatic chuck by the heat transfer gas. By controlling the pressure of the heat transfer gas supplied between the substrate G and the substrate 131 via the pipe 133 , the amount of heat transferred between the substrate 131 and the substrate G is adjusted. Moreover, in the base material 131 of the mounting table 130, the temperature control mechanism and temperature sensor (both not shown) for controlling the temperature of the board|substrate G are provided. Further, on the mounting table 130 , a plurality of lifting pins (not shown) for transferring the substrate G are provided so as to protrude from the upper surface of the substrate 131 .

An opening 155 for loading and unloading the substrate G is provided in the side wall 104a of the processing chamber 104 , and the opening 155 can be opened and closed by a gate valve V. When the gate valve V opens, carrying in and carrying out of the board|substrate G becomes possible via the opening 155.

Between the side wall 104a of the processing chamber 104 and the mounting table 130, for example, as shown in FIG. 2 , four sheets partitioning the interior of the processing chamber 104 into a processing space 106a and an exhaust space 106b. A partition member 158 is provided. The partition member 158 is a rectangular plate-shaped member having no opening. The partition member 158 is formed of, for example, a conductive material such as metal. One partition member 158 is provided between one of the side surfaces of the mounting table 130 and the side wall 104a of the processing chamber 104 . Each partition member 158 is grounded via the side wall 104a of the processing chamber 104 .

An opening 157 through which gas flows from the processing space 106a to the exhaust space 106b is formed between the adjacent partition members 158, for example, as shown in FIG. 2 . In the example of FIG. 2 , each opening 157 is present at the four corners of the mounting table 130 having a substantially rectangular shape in plan view.

A plurality of exhaust ports 159 are formed in the wall portion of the processing chamber 104 . In the present embodiment, the wall portion in which the plurality of exhaust ports 159 are formed is the bottom wall 104b of the processing chamber 104 . Each exhaust port 159 is provided with an exhaust mechanism 160 . The exhaust mechanism 160 includes an exhaust pipe 161 connected to the exhaust port 159, an Auto Pressure Controller (APC) valve 162 that controls the pressure in the processing chamber 104 by adjusting the opening degree, and the processing chamber ( 104) has a vacuum pump 163 for evacuating the inside. The inside of the processing chamber 104 is exhausted by the vacuum pump 163 and the opening degree of the APC valve 162 is adjusted, so that the pressure in the processing chamber 104 is maintained at a predetermined pressure.

The control device 20 has a memory, a processor, and an input/output interface. The processor in the control device 20 reads and executes a program stored in the memory in the control device 20 to control each part of the main body 10 via the input/output interface of the control device 20 .

[Details of the exhaust mechanism 160]

3 is an enlarged cross-sectional view showing an example of the exhaust mechanism 160 according to the first embodiment of the present disclosure. The exhaust mechanism 160 includes an exhaust pipe 161 , an APC valve 162 , a vacuum pump 163 , a foreign material mixing prevention net 164 , and a mesh member 30 . The foreign material mixing prevention net 164 is made of, for example, a metal containing stainless steel as a main component, and prevents the foreign material from entering the vacuum pump 163 .

The mesh member 30 is disposed in the vicinity of the exhaust port 159 formed in the bottom wall 104b of the processing chamber 104 . The mesh member 30 is formed in a plate shape with a metal mainly composed of aluminum or stainless steel. The mesh member 30 is supported by an exhaust pipe 161 . The exhaust pipe 161 is made of metal and is grounded via the bottom wall 104b. Accordingly, the mesh member 30 is grounded via the exhaust pipe 161 and the bottom wall 104b.

4 is a plan view showing an example of the mesh member 30 according to the first embodiment of the present disclosure. In the mesh member 30 , a plurality of through holes 31 penetrating in the thickness direction of the mesh member 30 are formed. In this embodiment, the shape of the opening of each through hole 31 is circular. Thereby, in the opening of the through hole 31, it is possible to suppress the concentration of the electric field. Moreover, although it is ideal that the shape of the opening of each through hole 31 is a true circle type, the shape of an ellipse, an elongate circle, etc. which the true circle shape is slightly flatly deformed may be sufficient.

5 : is an enlarged view for demonstrating an example of arrangement|positioning of the through-hole 31. As shown in FIG. In the present embodiment, as for the plurality of through-holes 31, the center O of each opening of the three adjacent through-holes 31 is, for example, any one of the three vertices of an equilateral triangle as shown in FIG. 5 . is arranged to be in the position of Such an arrangement of the through holes 31 is also called a 60° grid arrangement. Thereby, it is possible to efficiently arrange a large number of through holes 31 in the mesh member 30 , and it is possible to increase the exhaust conductance. In addition, when the shape of the opening is an ellipse or an elongated circle, the center O of the three adjacent through holes 31 forms an isosceles triangle instead of an equilateral triangle.

6 is an enlarged cross-sectional view showing an example of the mesh member 30 according to the first embodiment of the present disclosure. When the thickness of the mesh member 30 is Tn [mm] and the width of the opening of the through hole 31 is W [mm], the aspect ratio of the through hole 31 is R=Tn/W is defined as Since the shape of the opening of the through hole 31 in the present embodiment is circular, the width W of the opening of the through hole 31 is the diameter of the circular opening. The aspect ratio R of the through hole 31 in this embodiment is 0.67 or more.

In addition, when the shape of the opening of the through hole 31 is an ellipse or an elongated circle, the width of the narrowest portion is defined as the width W of the opening of the through hole 31 based on the relationship between the through hole and plasma, which will be described later. do. For example, when the shape of the opening of the through hole 31 is an ellipse, the width W of the opening of the through hole 31 is the short diameter of the elliptical opening. In addition, when the shape of the opening of the through hole 31' is, for example, an elongated circle as shown in FIG. 7, the width W of the opening of the through hole 31' is the narrower width of the opening widths. 7 is a view showing another example of the shape of the opening of the through hole 31'.

By providing the exhaust port 159 with the mesh member 30 in which the through hole 31 of a predetermined aspect ratio is formed, the intrusion of plasma into the through hole 31 is suppressed, and the inside of the through hole 31 is suppressed. Abnormal discharge is suppressed. Thereby, plasma processing in the processing space 106a can be stabilized.

[Experiment result]

8 to 11 are diagrams showing examples of experimental results in the first embodiment of the present disclosure. The experimental results illustrated in FIGS. 8 to 10 show the observation results of abnormal discharge when the mesh member 30 having a different thickness Tn and a different width W of the opening of the through hole 31 is used. In the experimental results illustrated in FIGS. 8 to 10 , plasma of O ₂ gas is generated in the processing space 106a for each combination of the pressure in the processing chamber 104 and the power of the high frequency bias supplied to the substrate 131 . In this case, the presence or absence of abnormal discharge in the vicinity of the exhaust port 159 was observed. In addition, the presence or absence of abnormal discharge is observed by the presence or absence of light emission in the through hole 31 . That is, when light emission is observed in the through hole 31, it is judged that an abnormal discharge has occurred.

In Fig. 8, a mesh member 30 having a thickness Tn of 5 mm, an opening width W of the through hole 31 of 5 mm, and an aspect ratio R of 1.0 was used. In Fig. 9, a mesh member 30 having a thickness Tn of 3 mm, an opening width W of the through hole 31 of 4 mm, and an aspect ratio R of 0.75 was used. In Fig. 10, a mesh member 30 having a thickness Tn of 2 mm, a width W of the opening of the through hole 31 of 3 mm, and an aspect ratio R of about 0.67 was used.

11 , CF ₄ gas and O ₂ gas are injected into the processing space 106a using the mesh member 30 having a thickness Tn of 5 mm and a width W of the opening of the through hole 31 of 5 mm. The observation result of the abnormal discharge in the case where the plasma of the mixed gas containing it is produced|generated is shown. 8 to 11 , "○" indicates that no abnormal discharge was observed in any of the through holes 31, and "x" indicates that abnormal discharge was observed in at least any one of the through holes 31. indicates that it has been

Referring to FIGS. 8 to 10 , as the power of the pressure and the high frequency bias increases, it can be seen that abnormal discharge tends to occur. In any of the cases illustrated in Figs. 8 to 10, no abnormal discharge was observed in most combinations of powers of pressure and high-frequency bias.

Moreover, as shown, for example in FIG. 11, the tendency for abnormal discharge to generate|occur|produce more easily as the electric power of a pressure and a high frequency bias became large was observed even if the gas type was changed. Also in the experimental results illustrated in Fig. 11, no abnormal discharge was observed in most combinations of the power of the pressure and the high frequency bias.

12 to 13 are schematic diagrams for explaining an example of the relationship between the through hole 31 and the plasma 51 . When plasma is generated, a sheath region 50 having a thickness of Ts is formed around the mesh member 30 that is a grounded metal. When the width W of the opening of the through hole 31 is larger than twice the thickness Ts of the sheath region 50, for example, as shown in FIG. 12 , the plasma 51 penetrates into the through hole 31, The abnormal discharge causes the plasma to become unstable. As a result, sufficient plasma is not generated at the location where the original plasma should be stably generated, and the processing of the substrate G is adversely affected.

On the other hand, for example, as shown in FIG. 13 , when the width W of the opening of the through hole 31 is equal to or less than twice the thickness Ts of the sheath region 50 , the plasma 51 does not penetrate into the through hole 31 . and abnormal discharge does not occur.

In addition, even if the width W of the opening of the through hole 31 is slightly larger than twice the thickness Ts of the sheath region 50, the space sandwiched between the sheath regions on both sides of the imaginary is equal to or less than the Debye length There the plasma becomes difficult to maintain in bulk. Therefore, it becomes difficult for the plasma to penetrate into the through hole 31 . In addition, when the thickness Tn of the mesh member 30 is large, the passage of charged particles from the plasma also becomes difficult, so that it is difficult to generate plasma even under the through hole 31 . Therefore, if the aspect ratio R of the through hole 31 of the mesh member 30 is equal to or greater than a predetermined value, it is considered that the plasma 51 does not penetrate into the through hole 31 and abnormal discharge does not occur.

[Comparative example]

Next, a comparative example is demonstrated. 14 is a plan view showing an example of the mesh member 40 in the comparative example. The mesh member 40 is formed in a plate shape with metal such as aluminum. The mesh member 40 is provided with a plurality of slits 41 penetrating in the thickness direction of the mesh member 40 . Each of the slits 41 has an elongated opening. The length in the longitudinal direction of the opening of the slit 41 is several millimeters to several tens of millimeters, for example, 80 millimeters. The length in the transverse direction of the opening of the slit 41 is 3.6 mm. Therefore, the width W of the slit 41 is 3.6 mm. In addition, the thickness Tn of the mesh member 40 is 2 mm. Accordingly, the aspect ratio R of each slit 41 is 0.56 in the transverse direction and 0.025 in the longitudinal direction. In addition, in evaluation of suppression of abnormal discharge, the aspect ratio of a transversal direction is employ|adopted as an aspect ratio of a slit.

15 is an enlarged cross-sectional view showing an example of an exhaust mechanism 160' in a comparative example. In the exhaust mechanism 160' in the comparative example, the mesh member 40 and the mesh member 43 are provided in the vicinity of the exhaust port 159, which is a typical configuration of the prior art. The mesh member 40 is provided in the opening of the exhaust pipe 161 and is grounded via the exhaust pipe 161 and the bottom wall 104b. The mesh member 43 has a structure different from that of the mesh member 40 , and is a member with a thickness of 0.8 mm in which openings 44 having a width of 4.2 mm are arranged at intervals of 0.8 mm. The mesh member 43 is disposed in the exhaust port 159 through the insulating member 42 . The mesh member 43 is electrically in a floating state. Other structures of the exhaust mechanism 160 are the same as those of the exhaust mechanism 160 described in FIG. 3 .

It is a figure which shows an example of the experimental result in a comparative example. 16 shows an observation result of abnormal discharge when plasma of O ₂ gas is generated in the processing space 106a for each combination of the pressure in the processing chamber 104 and the power of the high frequency bias supplied to the substrate 131 . is appearing In the comparative example, as illustrated in Fig. 16, abnormal discharge was observed in almost all combinations of the power of the pressure and the high frequency bias used in the experiment.

On the other hand, when the mesh member 30 in this embodiment is used, for example, as is clear from the experimental results of Figs. was hardly observed. Therefore, by using the mesh member 30 in the present embodiment, abnormal discharge in the through hole 31 can be suppressed, and plasma processing in the processing space 106a can be stabilized.

Here, since the surface of the mesh member 30 may be exposed to a corrosive gas in some cases, the mesh member 30 is preferably made of a metal having some resistance to the corrosive gas. The metal having a certain degree of resistance to corrosive gas is, for example, stainless steel, nickel, or a nickel alloy. As the nickel alloy, Hastelloy (registered trademark) can be used.

In addition, the temperature of the mesh member 30 may rise due to heat input from plasma. When the thermal conductivity of the mesh member 30 is low, the temperature gradient within the mesh member 30 increases, and the mesh member 30 may be thermally deformed. When the mesh member 30 bends due to thermal deformation, the contact area between the mesh member 30 and the exhaust pipe 161 decreases, and a potential difference may occur between the potential of the mesh member 30 and the ground potential. . When a potential difference occurs between the potential of the mesh member 30 and the ground potential, the potential difference between the plasma and the mesh member 30 decreases, so that the thickness of the sheath region 50 generated around the mesh member 30 decreases. and the plasma 51 easily penetrates into the through hole 31 .

The thermal conductivity of stainless steel or nickel alloy is about 10 to 30 W/m·K. In order to suppress the occurrence of abnormal discharge due to thermal deformation, it is preferably formed of a metal material having a thermal conductivity of 200 W/m·K or more. Since the thermal conductivity of aluminum is 236 W/m·K, the mesh member 30 is preferably made of, for example, a metal containing aluminum as a main component.

However, aluminum is easily corroded by the corrosive gas containing a halogen-type element. Therefore, when the mesh member 30 is formed of, for example, a metal containing aluminum as a main component, the surface of the mesh member 30 is preferably coated with a corrosion-resistant material having low corrosiveness to corrosive gas.

17 is a view showing an example of the amount of shearing of the mesh member 30 . In the experiment of FIG. 17 , the amount of shearing of the mesh member 30 was measured when plasma using a mixed gas of Cl ₂ gas and BCl ₃ gas (Cl ₂ : BCl ₃ = 2 : 1) was generated. When an Al ₂ O ₃ film having a thickness of 40 μm is formed on the surface of the mesh member 30 by anodizing the surface of the mesh member 30 made of aluminum, the amount of cut of the mesh member 30 is 101 Å/min. it was In addition, when a Y ₂ O ₃ film having a thickness of 200 μm is formed on the surface of the mesh member 30 by thermal spraying ceramics on the surface of the mesh member 30 made of aluminum, the amount of scraping of the mesh member 30 . was 70 Å/min. In addition, by performing dipping using a complex oxide on the surface of the mesh member 30 made of aluminum, a Cr ₂ O ₃ /Al ₂ O ₃ /SiO ₂ film having a thickness of 50 μm is formed on the surface of the mesh member 30 . In this case, the shearing amount of the mesh member 30 was 159 Å/min.

On the other hand, when the surface treatment was not performed on the mesh member 30 made of aluminum, the amount of shearing of the mesh member 30 was 2347 Å/min. In the case where the surface treatment was not performed on the mesh member 30 made of stainless steel, the amount of shaving of the mesh member 30 was 26 ANGSTROM /min.

From the experimental results of FIG. 17, for example, when formed of a metal material containing aluminum as a main component, the surface of the mesh member 30 is preferably coated with a corrosion-resistant material having low corrosiveness to corrosive gas. The corrosion-resistant material coated on the surface of the mesh member 30 may include, for example, Al ₂ O ₃ , Y ₂ O ₃ , and Cr ₂ O ₃ /Al ₂ O ₃ /SiO ₂ .

As mentioned above, 1st Embodiment was demonstrated. As described above, the plasma processing apparatus 1 according to the present embodiment includes a processing container 101 , a mounting table 130 , a gas supply mechanism 120 , an exhaust mechanism 160 , and a high frequency power supply. 115 , an antenna 113 , and a high frequency power supply 153 . The processing container 101 accommodates the substrate G. The mounting table 130 is provided in the processing container 101 , and the substrate G is mounted thereon. The gas supply mechanism 120 supplies a processing gas into the processing container 101 . The exhaust mechanism 160 exhausts the gas in the processing container 101 via the exhaust pipe 161 . The high frequency power supply 115 and the antenna 113 generate plasma in the processing vessel 101 by converting the processing gas supplied into the processing vessel 101 into plasma. The high frequency power supply 153 supplies high frequency power for bias to the mounting table 130 . The exhaust port 159 of the exhaust pipe 161 connected to the wall portion of the processing chamber 101 is provided with a mesh member 30 made of a conductive member and connected to a ground potential. In the mesh member 30 , a plurality of through holes 31 penetrating in the thickness direction of the mesh member 30 are formed. Further, in each through hole 31, the ratio of the thickness Tn of the mesh member 30 to the width W of the opening is 0.67 or more. Thereby, abnormal discharge in the vicinity of the exhaust port 159 can be suppressed.

In addition, in the above-described embodiment, the shape of the opening of each through hole 31 is circular, and the width W of the opening of the through hole 31 is the diameter of the opening. Since the shape of the opening of each through hole 31 is circular, it is possible to suppress the concentration of the electric field in the vicinity of the opening of the through hole 31 .

In addition, in the above-described embodiment, the diameter of the opening of each through hole 31 is not more than twice the thickness of the sheath formed around the mesh member 30 by plasma. In this way, the penetration of plasma into the through hole 31 of the mesh member 30 can be suppressed, and abnormal discharge in the through hole 31 can be suppressed.

In addition, in the above-described embodiment, the diameter of the opening of each through hole 31 is 5 mm or less. In this way, the penetration of plasma into the through hole 31 of the mesh member 30 can be suppressed, and abnormal discharge in the through hole 31 can be suppressed.

Further, in the mesh member 30 of the above-described embodiment, in the three adjacent through holes 31, the center of the opening of each through hole 31 is at any one of the three vertices of the equilateral triangle. placed so as to Thereby, a large number of through holes 31 can be arranged in the mesh member 30, and the exhaust conductance can be increased.

In addition, in the above-described embodiment, the mesh member 30 is stainless steel, nickel, or a nickel alloy. Thereby, even when plasma processing using a corrosive gas is performed, damage to the mesh member 30 by the corrosive gas can be reduced.

Further, in the above-described embodiment, the mesh member 30 is preferably formed of a material having a thermal conductivity of 200 W/m·K or more. For example, it is preferable that the mesh member 30 is formed of the metal which has aluminum as a main component. Thereby, the thermal deformation of the mesh member 30 can be suppressed, and the penetration of the plasma 51 into the through hole 31 can be suppressed.

In addition, in the above-described embodiment, the surface of the mesh member 30 is preferably coated with a corrosion-resistant material having a lower corrosiveness to a corrosive gas than a metal constituting the mesh member 30 . Thereby, even when plasma processing using a corrosive gas is performed, damage to the mesh member 30 by the corrosive gas can be reduced.

In addition, in the above-described embodiment, the wall portion in which the exhaust port 159 is formed is the bottom wall 104b of the processing container 101 . Accordingly, the gas in the processing container 101 can be efficiently exhausted.

(Second embodiment)

In the exhaust mechanism 160 in the first embodiment, one mesh member 30 is provided in the vicinity of the exhaust port 159 . In contrast, in the exhaust mechanism 160 according to the second embodiment, in the vicinity of the exhaust port 159, two mesh members 30 and a mesh member ( 33) is provided, which is different from the exhaust mechanism 160 in the first embodiment. In addition, since other configurations of the plasma processing apparatus 1 in the second embodiment are the same as in the exhaust mechanism 160 in the first embodiment, except for the points described below, they overlap. A description is omitted.

18 is an enlarged cross-sectional view showing an example of the exhaust mechanism 160 according to the second embodiment of the present disclosure. In the exhaust mechanism 160 in the present embodiment, the mesh member 30 and the mesh member 33 are provided in the vicinity of the exhaust port 159 . The mesh member 30 is provided in the opening of the exhaust pipe 161 and is grounded via the exhaust pipe 161 and the bottom wall 104b. The mesh member 33 has a structure different from that of the mesh member 30 , and is a member with a thickness of 0.8 mm in which 4.2 mm wide openings are arranged at intervals of 0.8 mm, similar to the mesh member 43 . The mesh member 33 is provided in the vicinity of the mesh member 30 on the opposite side of the exhaust pipe 161 with the mesh member 30 interposed therebetween. The mesh member 33 is disposed in the exhaust port 159 through the insulating member 32 , and is electrically floating. The mesh member 33 is an example of a floating mesh member. Other structures of the exhaust mechanism 160 are the same as those of the exhaust mechanism 160 described in FIG. 3 .

[Experiment result]

19 and 20 are diagrams showing examples of experimental results in the second embodiment of the present disclosure. The experimental results illustrated in Figs. 19 and 20 show the observation results of abnormal discharge when the mesh member 30 having a different thickness Tn and a different width W of the opening of the through hole is used. In the experimental results illustrated in FIGS. 19 and 20 , plasma of O ₂ gas is generated in the processing space 106a for each combination of the pressure in the processing chamber 104 and the power of the high frequency bias supplied to the substrate 131 . In this case, the presence or absence of abnormal discharge in the vicinity of the exhaust port 159 was observed.

In FIG. 19 , the mesh member 30 having a thickness Tn of 5 mm, the opening width W of the through hole 31 is 5 mm, and the aspect ratio R of 1.0, and the opening width W of the through hole 34 is 4.2. mm, a mesh member 33 having an aspect ratio R of 0.19 was used. In Fig. 20, the mesh member 30 having a thickness Tn of 7 mm, the opening width W of the through hole 31 is 7.5 mm, and the aspect ratio R of about 0.93, and the opening width W of the through hole 34 is A mesh member 33 of 4.2 mm and an aspect ratio R of 0.19 was used.

Referring to Figs. 19 and 20, as the power of the pressure and the high frequency bias increases, the abnormal discharge tends to occur more easily. In the experimental results illustrated in FIGS. 19 and 20 , compared to the experimental results of the comparative example (see FIG. 16 ) in which the aspect ratio of the slit 41 is 0.56 (see FIG. 16 ), the combination of the power of the pressure and the high frequency bias in which the abnormal discharge is observed is small. Therefore, also in the exhaust mechanism 160 in the second embodiment, the abnormal discharge in the vicinity of the exhaust port 159 can be suppressed than in the exhaust mechanism 160 ′ in the comparative example.

In addition, instead of the mesh member 30, a mesh member having the same structure as the mesh member 40 used in the comparative example except for the thickness Tn, and a mesh member having the same structure as the mesh member 33 or the mesh member 43 Even when two mesh members were used, the presence or absence of abnormal discharge in the vicinity of the exhaust port 159 was observed. It is a figure which shows an example of the experiment result in another embodiment of this indication. 21, the thickness Tn of the mesh member is 7 mm, the width W of the opening of the slit is 3.6 mm, and the aspect ratio R of the slit is 1.94.

In Fig. 21, the combination of pressure and high frequency bias power at which abnormal discharge is observed is greater than when the mesh member 30 having the through hole 31 having a circular opening is used. However, in FIG. 21 , as compared with the experimental results of the comparative example (see FIG. 16 ) in which the aspect ratio of the slit 41 is 0.55, the combination of pressure and high frequency bias power in which abnormal discharge is observed is small. Therefore, when the shape of the opening is a slit, the effect of suppressing abnormal discharge cannot be expected as much as when the shape of the opening is circular. can do. Therefore, the effect of suppressing abnormal discharge to a certain extent can be expected compared to the prior art. Moreover, although there is no restriction|limiting in particular about the length of the slit 41, For example, the structure used as the length of about 1/2 - 1/4 of the opening formation area as shown in FIG. 14 is preferable.

As mentioned above, 2nd Embodiment was demonstrated. As described above, in the plasma processing apparatus 1 according to the present embodiment, it is provided in the vicinity of the mesh member 30 on the opposite side of the exhaust pipe 161 with the mesh member 30 interposed therebetween, and is electrically floating. A mesh member 33 made of may be further provided. Also in this case, abnormal discharge in the vicinity of the exhaust port 159 can be suppressed.

[etc]

In addition, the technique disclosed in this application is not limited to the above-mentioned embodiment, Many modifications are possible within the scope of the summary.

For example, in each of the above embodiments, as an example of the plasma source, an inductively coupled plasma processing apparatus provided with a dielectric window has been described, but an inductively coupled plasma processing apparatus including a metal window may be used instead of the dielectric window. In addition, examples of plasma sources other than inductively coupled plasma include capacitively coupled plasma (CCP), microwave excited surface wave plasma (SWP), electron cycloton resonance plasma (ECP), and helicon wave excited plasma (HWP). there is.

In addition, it should be considered that embodiment disclosed this time is an illustration in all points, and is not restrictive. Indeed, the above-described embodiment may be embodied in various forms. In addition, said embodiment may be abbreviate|omitted, substituted, and may be changed in various forms, without deviating from the scope of the appended claims and the meaning.

V: gate valve
G: substrate
1: plasma processing device
10: body
101 processing vessel
102: dielectric wall
103: antenna room
103a: side wall
104: processing room
104a: side wall
104b: bottom wall
105: support shelf
106a: processing space
106b: exhaust space
111: shower housing
112: gas diffusion chamber
112a: gas discharge hole
113: antenna
113a: antenna wire
114: matching device
115: high frequency power
116: absence of power supply
117: spacer
118: terminal
119: feed line
120: gas supply mechanism
121: gas supply pipe
126: spacer
130: mount
131: description
132: protection member
133: plumbing
151: feed line
152: matching device
153: high frequency power
155: opening
157: opening
158: no partition
159: exhaust port
160: exhaust mechanism
161: exhaust pipe
162: APC valve
163: vacuum pump
164: foreign matter mixing prevention net
20: control unit
30: no mesh
31: through hole
32: insulation member
33: no mesh
34: through hole
40: no mesh
41: slit
42: insulation member
43: no mesh
44: opening
50: sheath area
51: plasma

Claims (10)

a processing vessel accommodating the substrate;
a mounting table provided in the processing vessel and on which the substrate is mounted;
a gas supply mechanism for supplying a processing gas into the processing container;
an exhaust mechanism for exhausting gas in the processing vessel through an exhaust pipe;
a plasma generating mechanism for generating plasma in the processing chamber by converting the processing gas supplied into the processing chamber into plasma;
A bias power supply mechanism for supplying high frequency power for biasing to the mounting table
to provide
An exhaust port of the exhaust pipe connected to the wall portion of the processing vessel is provided with a mesh member constituted by a conductive member and connected to a ground potential;
A plurality of through holes penetrating through the mesh member in a thickness direction of the mesh member are formed in the mesh member;
In each of the through holes, the ratio of the thickness of the mesh member to the width of the opening is 0.67 or more
plasma processing unit.
The method of claim 1,
The shape of the opening of each of the through holes is circular,
The width of the opening is the diameter of the opening
plasma processing unit.
3. The method of claim 2,
The diameter of the opening of each of the through holes is 5 mm or less.
4. The method according to claim 2 or 3,
The three adjacent through-holes are arranged so that the center of the opening of each of the through-holes is at any one of three vertices of an equilateral triangle.
4. The method according to any one of claims 1 to 3,
The mesh member is a plasma processing apparatus of stainless steel, nickel, or a nickel alloy.
4. The method according to any one of claims 1 to 3,
wherein the mesh member is formed of a material having a thermal conductivity of 200 W/m·K or more.
7. The method of claim 6,
wherein the mesh member is formed of a metal containing aluminum as a main component.
8. The method of claim 7,
A surface of the mesh member is coated with a corrosion-resistant material that is less corrosive to a corrosive gas than the metal.
4. The method according to any one of claims 1 to 3,
The wall portion in which the exhaust port is formed is a bottom wall of the processing vessel.
4. The method according to any one of claims 1 to 3,
and a floating mesh member provided in the vicinity of the mesh member on the opposite side of the exhaust pipe with the mesh member interposed therebetween and in an electrically floating state.

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